The overall objective of this research is to extract and purify tumor specific transplantation antigens from solid methylcholanthrene tumors from mice, and to determine their physical and chemical properties: molecular weight, carbohydrate content, disulfide bond content, and conformational stability. The antigens will be extracted first from tumor homogenates with a variety of chaotropic agents. They will be purified by gel filtration chromatography, ammonium sulfate precipitation, ion exchange chromatography, and finally by isoelectric focusing. The stages of purification will be monitored by a sensitive humoral cytotoxicity test already in use in our laboratories. We will study the subcellular origin of the antigens and attempt to localize them in membrane fractions. The possible shedding of the antigens from the cell surface will be studied by examining the supernatant fluids from the tissue cultured tumor cells. The methods developed for extraction of murine tumor antigens will be used to extract and purify antigens from human tumors.